1. Field of the Invention
This invention relates to a liquid crystal display device, which in a voltageless state is bright, having a liquid crystal layer placed in an active zone between substrates, the substrates each being covered on an outside by pole filters oriented in an arrangement for the voltageless bright display and on an inside carrying segments of surface electrodes. The segments are separated from one another by electrically insulating dividing lines, and the segments are connected to connection lines leading to the outside, and masking is provided for areas that otherwise remain bright in retrace blanking, on the inside of the substrate.
2. Discussion of Related Art
One liquid crystal display device is disclosed in U.S. Pat. No. 4,952,030. Such liquid crystal display devices for generating displays that are bright in the voltageless state have the advantage, over displays that are dark in the voltageless state, that the dark activated areas of the cells do not appear in color but instead are correctly black. The bright areas that are not activated are equally bright for light from all directions and thus the incident light is better utilized than in cells that are dark, when voltageless. The displays that are bright when voltageless can also be produced markedly less expensively, among other reasons because the dark background does not appear in color as a function of the viewing angle, and complicated countermeasures need not be taken to achieve a uniform color. In the cell that is bright when voltageless, the optical axes of the two polarization sheets are crossed. The non-activated areas are always bright, while the activated segments are conversely black. Thus even the region of the edge of the adhesive that encloses the liquid crystal area appears black. U.S. Pat. No. 4,952,030 teaches possible ways, in the case of displays that are bright when voltageless, of displaying bright segments on a dark background with good contrast and in particular even with an oblique viewing angle, for instance from a lower half-space. Thus, a twisting angle of the liquid crystal layer of <90° and in particular of 50° to 80° is recited. However, in such displays that are bright when voltageless, it is difficult to cause the bright non-activated areas to appear dark. For that purpose, the bright areas are covered with a light-absorbing mask, which to avoid parallax is usually placed on the inside of the substrate, as recited in U.S. Pat. No. 4,952,030. Masking is an expensive, complicated additional step in production.
A further liquid crystal display device for generating displays that are bright in the voltageless state is shown in German Patent Disclosure DE 37 82 916 A1 wherein a twisting angle of the liquid crystal layer of <90° is recited, for achieving favorable viewing from an oblique direction to the normal.